Never Owned a Tube Amp and Want Advice


Hi All, 

I have never owned a tube amplifier before and am planning to purchase one with a minimum of 50 watts per channel to mate with 8 ohm 88 dbl speakers.

My hope is experienced audiogoners will share their expertise regarding how to approach this. While I realize listening is the best way to learn about sound and compatibility; I want to learn a better understanding about brands with less maintenance and longer tube life, how to decide between mono or stereo,can a newbie play with bias or is auto biasing a better first choice, etc.

I would also appreciate what to look for in selecting a used tube amp to identify one that might be in need of repair. For example, with solid state depending on the brand, capacitor replacement can be more of a concern. Any advice on what to look out for or ask about with used tube amps would be appreciated.

A big question I have is how to understand the relationship between power tubes like E34's, 120.s, etc. and, I guess the driver? tubes like 12au7's and 12at7's. That  is to ask which is more critical to the overall sound of the amp? FWIW, I routinely tube roll with my preamps.  

I 've read through a number of threads but maybe someone can point me to good ones I may have missed. 

Thanks for listening,

Dsper
dsper
When I think of solid state, I understand that the continuous power rating is one thing and peak power supply is another.

My question is:

Is it true with tube amps that if an amp is rated at 60 wpc that is all you are going to get or do capacitors, power transformer, etc. come into play to allow higher peak power?
Peak power is an early 1970s thing. All amplifiers today are rated at continuous power. 

Now 'peak power supply' as you put it might be a current rating that has to do with what happens when you short out the power supply, and might be stated in amps. This is really a statement of how much energy is stored in the supply (and how big the spark will be when you short it out) rather than anything to do with how much power the amp makes.

Most tube amps are "optimistically" rated. That 60 watt tube amp might deliver that wattage at peak, but at 60 watts, it would be typically distorting quite a bit. Tube amps simply do not do well in a numbers game.  
This has nothing to do with tube or solid state and has everything to do with how conservative the manufacturer is with their ratings. We rate our amplifiers for RMS power into an 8 ohm load and we rate them to not be clipping at that power level. Now there are different definitions used by several measuring organizations such as Stereophile, but clipping technically speaking is when you see the test sine wave signal getting a flattened top and bottom- as if someone 'clipped' the top and bottom of the waveform off with a pair of scissors. That is why its called 'clipping'. Any other definition is arbitrary.
  For my taste, they are a touch lean (midrange on up being a bit more prominent than upper bass), but that is a matter of taste, and the good attributes of Atmasphere amps can be quite compelling.

Being more load sensitive, this has far more to do with how the amplifier is dealing with the load rather than the actual character of the amp itself. If you have it on a proper load (and the Tyler appears to be an excellent example) its not at all lean. The bigger the OTL, the less of an issue this is, IOW smaller OTLs are more load sensitive.


Now @larryi made a  good comment about amplifier clipping- if you plan to use a solid state amp, my surmise is you'll need to have about 200 watts to do what a 50-60 watt tube amp will seem to do on this speaker, entirely because of the simple fact that tube amplifiers clip (overload) so much more gracefully than solid state. When a solid state amp breaks up, its instantly audible even if its only for a few milliseconds. But in the case of a tube amp this isn't always true. They can overload so gracefully that it may not be apparent until the amp is really heavily overloaded. IME its important that the amplifier have instantaneous overload recovery- this is very helpful in minimizing the audible artifacts when the amp is briefly overloaded. This is why tube amplifier power seems to carry more weight than solid state.


Here we go again with the statement that tube watts are greater than S.S. watts. This statement is patently false and should call into question anything this member says in the future. Also, I maintain that impedance is more important in the greater scheme of things than efficiency when considering speakers with tube amps. Higher impedance speakers allow one to consider OTL amps which are the best I have heard.
Here we go again with the statement that tube watts are greater than S.S. watts. This statement is patently false and should call into question anything this member says in the future.

Are you sure you want to go there? "This member" didn't state that tube watts are greater than SS. He provided a very good, comprehensive explanation. "This member" should know, he's been designing high-end tube amps for at least 30 years.



Yes, Ralph was talking about clipping characteristics of solid state vs tube amps.

If you aren't driving the amps into clipping, then the clipping issue really isn't one.

It appears that a well designed and built tube amp in the 50-60 wpc range will work quite well with the speakers of choice mentioned.  It is always good to try the amp in you home system to make a final determination.  

But, there are some quite nice tube amps out there in the 50-60 wpc range.

enjoy
I rarely if ever disagree with Ralph and find his amps among the best I have ever heard. It was millercarbon that made the statement which I questioned. BTW this isnt the first time miller has made this statement about tubed vs S.S. watts.